Add a flag for enabling compositor property trees

content/renderer/gpu/render_widget_compositor.cc

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/renderer/gpu/render_widget_compositor.h"
 
 #include <limits>
 #include <string>
 
 #include "base/command_line.h"
@@ skipping 307 matching lines @@
       std::string top_threshold_str =
           cmd->GetSwitchValueASCII(cc::switches::kTopControlsHideThreshold);
       double hide_threshold;
       if (base::StringToDouble(top_threshold_str, &hide_threshold) &&
           hide_threshold >= 0.f && hide_threshold <= 1.f)
         settings.top_controls_hide_threshold = hide_threshold;
   }
 
   settings.verify_property_trees =
       cmd->HasSwitch(cc::switches::kEnablePropertyTreeVerification);
+  settings.use_property_trees =
+      cmd->HasSwitch(cc::switches::kEnableCompositorPropertyTrees);
   settings.renderer_settings.allow_antialiasing &=
       !cmd->HasSwitch(cc::switches::kDisableCompositedAntialiasing);
   // The means the renderer compositor has 2 possible modes:
   // - Threaded compositing with a scheduler.
   // - Single threaded compositing without a scheduler (for layout tests only).
   // Using the scheduler in layout tests introduces additional composite steps
   // that create flakiness.
   settings.single_thread_proxy_scheduler = false;
 
   // These flags should be mirrored by UI versions in ui/compositor/.
@@ skipping 741 matching lines @@
 #endif
   return actual;
 }
 
 void RenderWidgetCompositor::SetPaintedDeviceScaleFactor(
     float device_scale) {
   layer_tree_host_->SetPaintedDeviceScaleFactor(device_scale);
 }
 
 }  // namespace content